Device for converting biomass to reduced mediator, system for converting biomass to dihydrogen comprising it, and associated method

Patent metadata

Field	Value
Publication number	US-2023123627-A1
Application number	US-202117915537-A
Country	US
Kind code	A1
Filing date	Mar 30, 2021
Priority date	Mar 31, 2020
Publication date	Apr 20, 2023
Grant date	—

Abstract

A device for converting biomass into a redox mediator in reduced form, including an assembly of microbial fuel cells including a first compartment including an anode and fermentative microorganisms and electroactive microorganisms, and a second compartment including a cathode and a solution including the mediator, and an external resistor connecting the cathode and the anode. The value of the external resistance of at least one microbial fuel cell is distinct from that of at least one other microbial fuel cell. The device thus makes it possible to induce segregation of fermentative microorganisms and electroactive microorganisms along the assembly.

First claim

1 . A device for converting biomass to a redox mediator in a reduced form, comprising an assembly of several microbial fuel cells connected in series by a fluidic flow line, at least two microbial fuel cells each comprising:
a first compartment comprising an anode, fermentative microorganisms and electroactive microorganisms, and a second compartment comprising a cathode and a solution comprising the redox mediator, the first compartment and the second compartment being separated by a semi-permeable membrane, and an external resistance connecting the cathode to the anode, wherein a value of the external resistance of one of said at least two microbial fuel cells is distinct from the value of the external resistance of another of said at least two microbial fuel cells, so as to favour, in one of said at least two microbial fuel cells, the fermentative microorganisms relative to the electroactive microorganisms and, in the other of said at least two microbial fuel cells, the electroactive microorganisms relative to the fermentative microorganisms.

2 . The device according to claim 1 , wherein the value of the external resistance of a first microbial fuel cell of the assembly is less than or equal to the value of the external resistance of a second microbial fuel cell of the same assembly, the first microbial fuel cell being located before the second microbial fuel cell in a flow direction of a fluid in the flow line.

3 . The device according to claim 1 , wherein the value of the external resistance between at least some of the microbial fuel cells of the assembly is decreasing in a flow direction of a fluid in the flow line.

4 . The device according to claim 1 , wherein the assembly comprises a first group of microbial fuel cells and a second group of microbial fuel cells following in a flow direction of a fluid in the flow line, and the value of the external resistance R ext of at least one microbial fuel cell of the first group is between 0.8 R int <R ext <1.5 R int , with R int the value of the internal resistance of said cell.

5 . The device according to claim 1 , wherein the assembly comprising a first group of microbial fuel cells and a second group if microbial fuel cells following in a flow direction of a fluid in the flow line, and the value of the external resistance R ext of a microbial fuel cell of the second group, is between R int /10<R ext <4 R int /5, with R int the value of the internal resistance of said cell.

6 . The device according to claim 1 , wherein the mediator is buffered by an acid/base pair, such as a dihydrogen phosphate solution.

7 . (canceled)

8 . The device according to claim 1 , the device comprising several assemblies connected in parallel by the fluidic flow line.

9 . The device according to claim 1 , wherein the mediator has a redox potential in a range of +/−20%, preferably +/−10%, around its value under standard conditions at pH=7 and at a temperature of 25° C.

10 . The device according to claim 1 , wherein at least one from among the fermentative microorganisms and the electroactive microorganisms comes from an effluent sample from a purification station.

11 . A system for converting biomass to dihydrogen comprising:
a device for converting biomass to a redox mediator in a reduced form, according to claim 1 , and an electrolyser configured to produce dihydrogen from the mediator in reduced form.

12 . The system according to claim 11 , wherein the electrolyser is connected by a fluidic connecting line to the conversion device, the fluidic connecting line being configured to drive, by a first portion, the mediator of the conversion device to the electrolyser and to drive by a second portion, the mediator of the electrolyser to the conversion device.

13 . The system according to claim 11 , wherein a deviation distance between an anode and a cathode of the electrolyser is greater than 2 mm.

14 . A method for converting biomass comprising:
a supply of biomass to a device for converting biomass to a redox mediator in a reduced form, comprising an assembly of several microbial fuel cells connected in series by a fluidic flow line, at least two microbial fuel cells each comprising:
a first compartment comprising an anode, fermentative microorganisms and electroactive microorganisms,
a second compartment comprising a cathode and a solution comprising a redox mediator, the first compartment and the second compartment being separated by a semi-permeable membrane,
an external resistance connecting the cathode and the anode, and
an adjustment of a value of the external resistance of one of said at least two microbial fuel cells such that the value of said external resistance is distinct from the value of the external resistance of the other of said at least two microbial fuel cells, and a conversion of the biomass at least to organic acids by the fermentative microorganisms, and a reduction of the mediator of an oxidised form to a reduced form by the electroactive microorganisms,
so as to favour, in one of said at least two microbial fuel cells, the fermentative microorganisms relative to the electroactive microorganisms and, in the other of said at least two microbial fuel cells, the electroactive microorganisms relative to the fermentative microorganisms.

15 . The method according to claim 14 , wherein the value of the external resistance of at least one microbial fuel cell is adjusted according to a load of the biomass.

16 . The method according to claim 14 , wherein the value of the external resistance of at least one microbial fuel cell is adjusted so as to be between R int /10<R ext <4 R int /5 when a concentration of acetate measured at the input of said microbial fuel cell is greater than 5 mM, with R int the value of the internal resistance of said cell, the method comprising beforehand to said adjustment, a measurement of the concentration of acetate at the input of said microbial fuel cell.

17 . The method according to claim 14 , wherein the adjustment of the value of the external resistance of at least one microbial fuel cell is done at regular intervals.

18 . The method according to claim 14 , further comprising a supply of the mediator in reduced form to an electrolyser and a production of dihydrogen by the electrolyser from the mediator in reduced form.

19 . The system according to claim 11 , wherein the mediator exhibits a redox potential in a range of +/−20%, preferably +/−10%, around its value under standard conditions at ph=7 and at a temperature of 25° C.

20 . The system according to claim 11 , wherein the anode of the electrolyser is of an active surface at least equal to double, preferably triple, an active surface of a cathode of the electrolyser.

21 . The system according to claim 11 , wherein the electrolyser is exempt of a semi-permeable membrane.

Assignees

• Univ Grenoble Alpes
• Centre Nat Rech Scient
• Inst Polytechnique Grenoble
• Univ Savoie Mont Blanc

Inventors

• Belleville Pierre
• Deseure Jonathan
• Merlin Gérard

Classifications

• C02F3/005 Primary

  Combined electrochemical biological processes (aeration by electrolytically produced oxygen bubbles C02F3/202) · CPC title

• C02F2303/10

  Energy recovery · CPC title

• C25B1/02

  Hydrogen or oxygen · CPC title

• C25B3/25

  Reduction · CPC title

• C25B15/023

  Measuring, analysing or testing during electrolytic production · CPC title